Commutator device for a direct current micro-motor



Dec. 29, 1959 MATSUO MISHIMA 2,919,360v

COMMUTATOR DEVICE FOR A DIRECT CURRENT MICRO-MOTOR V Filed July 31, 1956 INVEN TOR m4 731 0 fl/Sfl/MA BY @W, (Jaw- A *4 ATTORNEYS.

3v tion to generators, can be made without departing from the spirit and scope of the invention.

What I claim is:

1. In a commutator device. formicro-dynamo electric machines having a rotary armature provided with a cornmutator, the combination comprising a rotatablyjournalled shaft, a brush wheel fixed at one end of said shaft and having a peripheral rim with an annular surface in rolling contact with the commutator periphery, electrical contact spring means at the other end of said shaft for pressing said brush wheel rim resiliently into contact with the commutator, and simultaneously maintaining electrical contact with said shaft, said brush wheel being so ar ranged with respect to said commutator that portions of the annular rim surface thereof contacting said commutator periphery surface, slide with respect to said commutator during rotation of the armature, for the maintenance of low electrical contact resistance between the surfaces and electrical conducting means connected to said spring means.

2. In a commutator device for micro-dynamo electric machines having a rotary armature provided with a commutator, the combination comprising a rotatably journalled shaft, extending substantially perpendicular with respect to the axis of rotation of the armature, a brush wheel fixed at one end of said shaft and having a: peripheral rim with an annular surface in rolling contact with the commutator periphery, and spring means at the other end of said shaft for pressing said brush wheel rim resiliently into contact with the commutator and simultaneously maintaining electrical contact with said shaft, said brush wheel being so arranged with respect to said commutator that portions of the annular rim surface thereof contacting said commutator periphery surface slide with respect to said commutator during rotation of the armature, whereby said contacting surfaces are continually lapped clean for the maintenance of low electrical contact resistance therebetween, and electrical. conducting means connected to said spring means.

3. The invention as defined in claim 2, wherein said shaft is journalled between a pair of axially-spaced oilless bearing members.

4. In a commutator device for micro-dyamo electric machines having a rotary armature provided with a. cornmutator, the combination comprising a rotat'ably journalled shaft, extending substantially perpendicular with respect to the axis of rotation of the armature, a brush wheel fixed at one end of said shaft and having a peripheral rim with an annular surface in rolling contact with the commutattor periphery, a pivot member secured to the other end of said shaft, a disc-like concave thrust bearing member abutting against said pivot member with its concave side, a helical spring acting in compression against the convex side of said thrust bearing, said brush wheel rim being resiliently pressed thereby to contact with said commutator and electrical contact being thereby simultaneously maintained between said thrust hearing member and said shaft, said brush wheel being so arranged with respect to said commutator that portions of the annular rim surface thereof contacting said commutator periphery surface slide with respect to said commutator during rotation of the armature, whereby said contacting surfaces are continually lapped clean for the maintenance of low electrical contact resistance therebetween and electrical conducting means connected to said concave thrust bearing member.

5. The invention as defined in claim 4, including means for adjusting the compressional force exerted by said helical spring against said convex side of said concave thrust bearing.

6. The combination according to claim 1, wherein said shaft is pivotally supported to assume angular positions with respect to the axis of rotation of said commutator.

7. In a commutator device for microdynamo electric machines having a rotary armature provided with a commutator, the combination comprising a rotatably journalled shaft, a brush wheel fixed at one end of said shaft and having a peripheral rim with an annular surface in contact with the commutator periphery, electrical contact spring means at the other end of said shaft for pressing said brush wheel rim resiliently into contact with the commutator and simultaneously maintaining electrical contact with said shaft, a bearing means rotatably supporting said shaft and permitting rolling and sliding movement of said annular surface in contact with the commutator periphery, whereby said brush wheel maintains continuous electric contact with the commutator at low contact pressure and with minimum dynamic electrical contact resistance.

8. The combination according to claim 7, wherein said shaft extends substantially perpendicular to the axis of rotation of said armature.

9. The combination according to claim 7, wherein said shaft is pivotally supported to assume angular positions with respect to the axis of rotation of the armature.

References Cited in the file of this patent UNITED STATES PATENTS 228,116 Randall May 25, 1880 337,885 Stockwell Mar. 16, 1886 399,329 Heywood Mar. 12, 1889 788,291 Titzel Apr. 25, 1905 FOREIGN PATENTS 5,668 Great Britain of 1881 124,258 Germany Oct. I5, 1901 

